The contents of food cans dented for instance by a fall are no longer suitable for human consumption because the protective inner foil for example is damaged. Equally unsuitable for human consumption are the contents of food cans wherein a determined period of time, for instance one or two years, has passed since the filling date.
Up to the present, such cans have been placed in the environment in filled state, usually with the domestic refuse at a dump-site. For environmental reasons resulting from the presence of metal, this is no longer permitted. Such food cans no longer fit for use were also destroyed in incinerators. However, the processing price has recently increased very sharply.